If you’ve read any review I’ve ever done about photography gear, then you know that I am convinced that cheaper is never better. When I first started doing photography, I never thought I’d say that. I couldn’t see the difference and, after all, a camera is a camera. In short order, I learned I was wrong. I bought a cheap memory card, and it failed quickly. I bought cheap replacement batteries, and they ended up in the trash quickly. I could go on, however, I am sure you get the point.
If you think about it, camera bodies come and go. Even though people are replacing cameras far less often than they did, eventually, you will replace your camera or camera body. It is likely you won’t change brands. You might move from a cropped sensor to a full sensor as your skill level increases, but most people just buy the most recent version of the camera they now own. The reason is rather obvious: Lenses designed for full-frame sensor cameras don’t work well, if at all, on cameras with cropped sensors and vice versa. Replacing lenses gets expensive quickly, and used photography gear isn’t much different than trying to get what you paid for a car after you drive it off the lot.
Unless you purchase a point-and-shoot camera, you want to preserve the investment you will make in lenses. In most cases, unless you drop a lens or it fails and isn’t worth repairing, you will keep your lenses most of your life. My favorite lens is more than 50 years old and predates the birth of digital cameras. When I add what I paid for that lens to the two other 6×7 camera lenses I own plus the four 645 lenses, I have easily invested enough to have purchased another 645Z from Pentax. That’s only because none of my lenses were purchased new. If I had bought them new….
Filters are like lenses. A good one will last forever. A good one will do what you need done while minimally distorting the image, will not cause colors to be inaccurately displayed, nor will it degrade overall image quality. Some inexpensive ND filters even add an “X” over an image which you must remove in post processing. Why does this happen? That takes us into technical territory.
There are three critical components that determine the quality of a filter:
1 The clarity of the glass.
2 The thickness of the filter.
3 The quality of the coatings.
We have been conditioned not to think about the clarity of glass. Compared to windows made even 200 years ago, we see glass as perfectly transparent. In fact, this isn’t true. Manufacturing glass is a complex process that involves a number of substances that themselves are not transparent. Which substances are used, the ratios in which they are combined, and ultimately how the glass produced is cooled, all shape the clarity of the glass. Even if we can’t see it, “dirt” suspended in this glass, or random malformations of the molecules in the glass, all contribute to the loss of clarity. The less clarity, the more the visual distortion, loss of color, vignetting.
With respect to the clarity – or purity might be a better word – of the glass, Sirui manufactures its filters from German Schott Plate Glass B270, one of the clearest glass products available. Schott Plate Glass offers a luminous transmittance of 91.7% which means nearly 92% of the light that strikes the surface of the glass passes through. Filters that are far less expensive use plastic. While the luminous transmittance of plastic varies, as does the luminous transmittance of glass, based upon the quality of the manufacturing process, in the end, from all I read, glass is still better suited for use in lenses and filters.
With respect to the thickness of the filter, the thicker the filter the more likely it is that some form or visual distortion, color loss, vignetting, or loss of light will occur. Also, if you stack filters as I did, the loss of quality is compounded with each filter added. The Sirui filters are exceptionally thin: 2.8 MM. Two stacked are smaller than single filters from other manufacturers. The rim of the filter is made from aircraft-grade aluminum. While other manufacturers use brass or steel, the aircraft aluminum frame is lighter and just as stable.
As I learned doing research for this review, the subject of coatings is highly technical and almost as highly debated. Some manufacturers use single layer coatings while others use multi-layer coatings. At some point in the last decade, nano-coatings have entered the market. Theoretically, nano-coatings have physical features small enough that light is not reflected at all. Less light reflected by a filter or in a lens translates into better images. As one person put it –
Most camera lenses have been multicoated for decades now. Before that (from around the ’50s to the ’70s) they were single coated. Before that, most were un-coated.
Uncoated lenses typically lose around 4-8% to reflection.
Single-coated lenses lose around 2-4% to reflection.
Multicoated lenses lose around 0.5-1% to reflection.
Nanocoated/SWC lenses lose around 0.05-0.1% to reflection.
Whether or not the difference between .5% and .05% is substantial, ever little bit helps.
Sirui offers three options:
1 Traditional round ND filters
2 Rectangular ND filters
3 Graduated ND filters.
If you aren’t familiar with the last option, graduated ND filters are very similar in design to circular polarized filters. Over the face of the filter the intensity or density of the coating diminishes. One end is fully coated and the other has no coating. We tested only the traditional round ND filters.
We were very impressed with every aspect of the images we produced:
1 There was no visible color caste or color shift. I should note that we only work in Raw and the cornerstone of our post processing is DxO Labs’ PhotoLab 2. I can’t see any color caste when I look at the images there prior to processing them, though I can’t guarantee that PhotoLab isn’t automatically removing any caste that might exist.
2 There was no vignetting. Images were crisp end to end.
3 Detail remained superb. Even at 100%, I didn’t see any loss of detail.
I do have some minor – very minor – concerns about the packaging.
1 There is a sticker on one side of each filter that tells you to remove the protective plastic from the other side. Removing that plastic protector is hard for someone like me with larger than average fingers. It would have made more sense for the sticker to actually be on the removable plastic.
2 The white plastic case each filter comes in is awesome. Strong and easy to carry. However, be careful when you open the case – especially for the first time. The first time I opened the carrying case the filter almost fell to the ground. Make sure the word “Sirui” is on the top, facing you.
Despite these issues, these are fantastic filters for a very good price. They compare extremely well to more expensive filters from better known companies.
In future reviews we will look at other Sirui options – the rectangular ND filers and the graduated ND filters. Visit Sirui USA here.